Heater



FIG. 1 is a front perspective view of a heater, showing my new design and shown with the front and side doors closed;

FIG. 2 is a right front perspective view thereof, shown with the front and side doors opened;

FIG. 3 is a left front perspective view thereof;

FIG. 4 is another perspective view of the heater as shown in FIG. 1;

FIG. 5 is a rear perspective view thereof; and

FIG 6 is a top perspective view thereof. 

The ornamental design for a heater, as shown. 